Blackfoot Lodge Tales, by George Bird Grinnell, [1892], at sacred-texts.com
A small stone, which is usually a fossil shell of some kind, is known by the Blackfeet as I-nis´-kim, the buffalo stone. This object is strong medicine, and, as indicated in some of these stories, gives its possessor great power with buffalo. The stone is found on the prairie, and the person who succeeds in obtaining one is regarded as very fortunate. Sometimes a man, who is riding along on the prairie, will hear a peculiar faint chirp, such as a little bird might utter. The sound he knows is made by a buffalo rock. He stops and searches on the ground for the rock, and if he cannot find it, marks the place and very likely returns next day, either alone or with others from the camp, to look for it again. If it is found, there is great rejoicing. How the first buffalo rock was obtained, and its power made known, is told in the following story.
Long ago, in the winter time, the buffalo suddenly disappeared. The snow was so deep that the people could not move in search of them, for in those days they had no horses. So the hunters killed deer, elk, and other small game along the river bottoms, and when these were all killed off or driven away, the people began to starve.
One day, a young married man killed a jack-rabbit. He was so hungry that he ran home as fast as he could, and told one of his wives to hurry and get some water to cook it. While the young woman was going along the path to the river, she heard a beautiful song. It sounded close by, but she looked all around and could see no one.
The song seemed to come from a cotton-wood tree near the path. Looking closely at this tree she saw a queer rock jammed in a fork, where the tree was split, and with it a few hairs from a buffalo, which had rubbed there. The woman was frightened and dared not pass the tree. Pretty soon the singing stopped, and the I-nis´-kim [buffalo rock] spoke to the woman and said: "Take me to your lodge, and when it is dark, call in the people and teach them the song you have just heard. Pray, too, that you may not starve, and that the buffalo may come back. Do this, and when day comes, your hearts will be glad."
The woman went on and got some water, and when she came back, took the rock and gave it to her husband, telling him about the song and what the rock had said. As soon as it was dark, the man called the chiefs and old men to his lodge, and his wife taught them this song. They prayed, too, as the rock had said should be done. Before long, they heard a noise far off. It was the tramp of a great herd of buffalo coming. Then they knew that the rock was very powerful, and, ever since that, the people have taken care of it and prayed to it.
[NOTE.I-nis´-kims are usually small Ammonites, or sections of Baculites, or sometimes merely oddly shaped nodules of flint. It is said of them that if an I-nis´-kim is wrapped up and left undisturbed for a long time, it will have young ones; two small stones similar in shape to the original one will be found in the package with it.]